The method an apparatus described herein manages uplink resources to increase spectral efficiency and system capacity. According to one embodiment of the present invention, a base station may be assigned two or more downlink carriers for downlink transmission and two or more corresponding uplink carriers. In a multi-carrier mode, the base station may transmit signals on two or more downlink carriers to the same mobile terminal, and receive signals from the mobile terminal on one of the paired uplink terminals. The uplink carriers can be operated at different interference levels and the uplink traffic can be divided between the available uplink carriers based on the type of traffic and/or data transmission parameters. The mobile terminals may also be allowed to switch between the uplink carriers to improve overall efficiency.